Abstract

Background

The gold standard treatment for early stage non small-cell lung cancer (NSCLC) is surgical resection. For patients (pts) considered medically or functionally not amenable with surgery, radiotherapy is the alternative treatment. In the last years impressive local control (LC) rates have been reported using stereotactic radiotherapy treatment (SBRT) that provides an attractive option to deliver high dose per fraction and a high biological equivalent dose (BED). The purpose of our study is to evaluate outcome and follow-up data on our pts who underwent Cyberknife (CK) Radiosurgery for early NSCLC.

Methods

Since February 2005 to October 2013, a total of 90 pts, median age of 76 years (range 42–90) with pathologically proven NSCLC, diagnosed as 41 stage IA and 56 stage IB were referred to our Radiotherapy Department for CK-SBRT. Selected tracking modalities depended on tumor size, location and extent of respiratory movement were performed. 27 pts with lower lobe lesions were treated with fiducial markers (1–3), in the others 70 fiducialless X sight option was used. The median tumor volume was 30 cc (range, 4–143). Depending on tumor size and location different curative dose regimens were used, but in all pts a high BED (>100 Gy) was delivered to the tumor. The SBRT treatment dose of 25–60 Gy was prescribed to the 75–85% isodose lines in 1–5 fractions. Median follow-up was 30 months (range, 2–102).

Results

The Kaplan–Meier LC rate at 1, 3 and 5 years was respectively 98%, 88.5% and 81%. Reported acute side effects have generally been mild including esophagitis, fatigue, chest wall tenderness and cough. For the evaluation of toxicity we used the RTOG/EORTC scale. We detected a late radiation-induced local fibrosis using CT imaging in most pts, in 3 we observed grade 3 pneumonitis, in 1 patient chest wall pain and rib fracture and in another one G3 radiation induced mielopathy at an interval of 30 months following CK/SRS treatment.

Conclusions

CK/SBRT for limited-stage primary lung cancer has been shown to be a promising treatment with high LC rates and very low toxicity. Prospective studies should be performed to determine whether this therapy may be an alternative option for surgery.